register

# File actionpack/lib/action_dispatch/http/mime_type.rb, line 101
      def register(string, symbol, mime_type_synonyms = [], extension_synonyms = [], skip_lookup = false)
        Mime.const_set(symbol.to_s.upcase, Type.new(string, symbol, mime_type_synonyms))

        SET << Mime.const_get(symbol.to_s.upcase)

        ([string] + mime_type_synonyms).each { |str| LOOKUP[str] = SET.last } unless skip_lookup
        ([symbol] + extension_synonyms).each { |ext| EXTENSION_LOOKUP[ext.to_s] = SET.last }
      end